This invention relates to a system that monitors two sensor signals to determine direction of movement of an object so that position of the object can be more accurately determined.
Many different types of control systems monitor various characteristics of an object in order to make control decisions. For example, sensors can monitor and generate data that can be used to determine speed, position, and/or direction of movement of the object. Direction is determined by comparing two sensor signals to each other and position is incremented or decremented according to the direction. A system micro controller calculates position. It is important that a determination of direction of movement be accurate so that position can be accurately determined. Misjudgments of the direction can result in error in position calculation.
Misjudgments can occur either by a signal phase shift or by noise. The phase shift is caused by imbalance between the two sensors and/or imbalance between the interface circuits for the sensors. Noise can also cause misjudgments. For example, if the first sensor turns high from low due to noise when a rising edge of the second sensor is received, the direction of movement can be misjudged.
Thus, it is desirable to have a system that can more accurately determine direction of movement of an object to increase accuracy of position determination.